Does using International SOS amount to having travel insurance?

If a business has a contract with a company such as International SOS, does this amount to having travel insurance?

Or could the individuals traveling for work with this business still be liable for potential out-of-pocket medical expenses?

I had assumed that using International SOS - and similar companies - did amount to having travel insurance, but I've just noticed that they don't really specify that they provide insurance. They do, however, appear to provide services that are often paid for by travel insurance.

For example, Wikipedia says:

International SOS specialises in medical assistance, travel security advice and information, emergency services, healthcare, evacuation and repatriation services.

Apart from the security advice and information, all of these services are usually covered under travel insurance. Obviously coverage for cancellations and lost/stolen luggage don't appear to be covered by International SOS; I'm more concerned about medical expenses as these are the 'unknowns' that can get quickly out of control in an emergency.

So my question is... as a traveler traveling with my employer, covered by an International SOS plan, am I good, medical-insurance wise? Or should I be asking my employer to take out additional travel insurance?

As a followup question that could potentially help define this, what if it was a trip requiring a Schengen visa - would this meet the Schengen travel insurance requirements?

EDIT: The business is on the 'Corporate Comprehensive Program', if that helps. Peter in the comments found a link to the personal membership plan comparisons, which might provide some of the puzzle pieces.